CODEWITHSUNDEEP
c++qtopenglsvg
ricky
ricky

Reputation: 2108

Why qt have better performance when render svg file in opengl than in native

Sorry if it sounds stupid. I'm new to QT world.

I'm running SVG Viewer Example from QT official website. And I find out that the performance is very different in Native mode and OpenGL mode.

Basically the different of this two mode is that. In native mode, its viewport is a QWidget; in OpenGl mode, its viewport is a QGLWidget.

My question is what leads to the performance difference? Is there any online document about this?

enter image description here

Upvotes: 2

Views: 1248

Answers (1)

Steeve
Steeve

Reputation: 1341

The performance is not necessarily different, but the CPU usage is. That is because OpenGL moves the calculations onto the GPU.

You can think of OpenGL basically as an API for programming the GPU.

When you switch to "Native", all calculations like the rasterization of the SVG data is done on the CPU, which is what you can see in the Task Manager.

Upvotes: 7

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